Geneva's and Switzerland's first trams ran on 19 June 1862, with the opening of a horsecar tramway between Place Neuve and Carouge.

Finally, in 1899, the Compagnie Genevoise des Tramways Électriques (CGTE), predecessor of the TPG, was inaugurated.

The good technical condition of the tramcars and the fact that they had not yet been written off, led to the provisional retention of the last tramway.

In the 1970s, concepts were developed to connect the relatively large suburban communities of Meyrin and Onex to the remaining tramway once again, with an appropriately modern light railway.

However, all of these ideas, and also the investments necessary for the maintenance of the remaining infrastructure in the medium term, exceeded the abilities of the privately owned CGTE.

However, it was only on 12 June 1988, with the adoption of a new cantonal law about public transport, that the first concrete building proposals were presented.

To connect the new facility with the existing network, the route of line 12 was extended on 27 September 1987 by one kilometre (0.6 mi) from Carouge to Bachet.

The sidings and maintenance facility in Bachet were opened in 1988, and in 1990 the associated tram and trackwork construction workshop was commissioned.

The colloquial expression "DAV", which is used to denote these vehicles, is an acronym for Düwag - Ateliers de Vevey.

The following year, on 11 December 2004, line 15 entered service; it ran on a new route from Lancy-Pont-Rouge via Acacias to Plainpalais, and continued from there via Cornavin station to Nations.

On 13 May 2006, upon the entry into service of a new section between Palettes and Lancy-Pont-Rouge, the ring link was completed, and with it the first phase of the network's expansion.

According to various sources, the opening of the second stage of the TCMC (Avanchet–Meyrin) took place on 12 December 2009, with the entry into service of the section to Meyrin (Gravière).

The first – very short – section of this route, between Coutance and Genève-Cornavin station, had already commenced operations at the timetable change in December 2010.

For the inauguration of the TCOB route, the TPG ordered 32 Tango trams, made by the Swiss company Stadler Rail.

Although these changes simplify tram operations, they also mean that points on the inner city sections, and in particular Genève-Cornavin station, can no longer be reached from all parts of the network (e.g. Genève-Cornavin is no longer directly served by line 12) without the need to change trams en route.